Using kICS to Reveal Changed Membrane Diffusion of AQP-9 Treated with Drugs

Jakob L Kure; Thommie Karlsson; Camilla B Andersen; B Christoffer Lagerholm; Vesa Loitto; Karl-Eric Magnusson; Eva C Arnspang

doi:10.3390/membranes11080568

Using kICS to Reveal Changed Membrane Diffusion of AQP-9 Treated with Drugs

Membranes (Basel). 2021 Jul 28;11(8):568. doi: 10.3390/membranes11080568.

Authors

Jakob L Kure¹, Thommie Karlsson^{2

3}, Camilla B Andersen¹, B Christoffer Lagerholm^{3

4}, Vesa Loitto⁵, Karl-Eric Magnusson⁵, Eva C Arnspang^{1

3}

Affiliations

¹ SDU Biotechnology, Department of Green Technology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
² Division of Medical Microbiology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden.
³ MEMPHYS, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
⁴ Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, UK.
⁵ Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden.

Abstract

The formation of nanodomains in the plasma membrane are thought to be part of membrane proteins regulation and signaling. Plasma membrane proteins are often investigated by analyzing the lateral mobility. k-space ICS (kICS) is a powerful image correlation spectroscopy (ICS) technique and a valuable supplement to fluorescence correlation spectroscopy (FCS). Here, we study the diffusion of aquaporin-9 (AQP9) in the plasma membrane, and the effect of different membrane and cytoskeleton affecting drugs, and therefore nanodomain perturbing, using kICS. We measured the diffusion coefficient of AQP9 after addition of these drugs using live cell Total Internal Reflection Fluorescence imaging on HEK-293 cells. The actin polymerization inhibitors Cytochalasin D and Latrunculin A do not affect the diffusion coefficient of AQP9. Methyl-β-Cyclodextrin decreases GFP-AQP9 diffusion coefficient in the plasma membrane. Human epidermal growth factor led to an increase in the diffusion coefficient of AQP9. These findings led to the conclusion that kICS can be used to measure diffusion AQP9, and suggests that the AQP9 is not part of nanodomains.

Keywords: diffusion; image correlation spectroscopy; kICS; nano-domains; plasma membrane.

Grants and funding

19105/Villum Fonden